cannot figure out the problem. i have a 2002 4.6 w/102000mi and the idle is bad. when i come to a red light, or park my truck it sounds like i am sitting ther pushing on the gas and letting it off, it revs up and down and sometimes stalls. it does it worse if the a/c is running. i changed out the coils, plugs(ngk), egr valve, cleaned the throttle body,iac valve, and maf sensor and followed the directions. My truck at idle runs really rich and i dont know what the problem is. before i changed anything, the truck was ran thru a lot of water and after that problems occured and everytime i replaced something it ran better, but it still dont run right. if i cant figure it iut im going to take it to a mechanic. any ideas thanks

 

I know you mentioned the IAC in your post, however did you replace it or clean it? I would just replace the part as that would have a lot to do with your idle issue, more specifically the rev issue you are facing. There are others with more experience and can offer some other suggestions.

 

i just cleaned it. if the iac is bad, would that be the reason it revs up and down??

 

You might get better help if you stop opening new threads - keeping it in a single thread will let everyone actually see what has already been done and see suggestions of others.

 

It is very likely to be the case. Do you have any codes coming up?

 

if there are no vaccume leaks replace IAC

 

Sorry dude i guess i killed your thread.
You know there is no tollarance here.
they've been in this forum for a long time and don't understan this can be confusing to beginers :o